"We've had a great run together - one of the most successful in Hollywood history - and it's a shame that Disney won't be participating in Pixar's future successes," he said.

Pixar said it would complete the two films it is already committed to making with Disney - The Incredibles in 2004 and Cars in 2005.

After that, Pixar said, it "intends to retain full ownership of its future productions".

Disney will retain the rights to distribute Pixar's first seven films, with Pixar continuing to receive its current share of the profits.

Wrangles at Disney

"Although we would have enjoyed continuing our successful collaboration under mutually acceptable terms, Pixar understandably has chosen to go its own way to grow as an independent company," Disney's chief executive, Michael Eisner said in a statement.

Analysts say the announcement comes at a bad time for Mr Eisner.

His long-term strategy for Disney has been heavily criticised by some shareholders, while Roy Disney, the nephew of the company's founder Walt, has been leading a vigorous campaign to have him sacked.

Finding Nemo, the cartoon about a clownfish searching for his missing son, has been nominated for four awards at this year's Oscars, including best animated feature film.